1. Field of the Disclosure
The technology of the disclosure relates to distributed antenna systems for distributing radio frequency (RF) signals to remote antenna units.
2. Technical Background
Wireless communication is rapidly growing, with ever-increasing demands for high-speed mobile data communication. As an example, so-called “wireless fidelity” or “WiFi” systems and wireless local area networks (WLANs) are being deployed in many different types of areas (e.g., coffee shops, airports, libraries, etc.). Distributed antenna systems communicate with wireless devices called “clients,” which must reside within the wireless range or “cell coverage area” in order to communicate with an access point device.
One approach to deploying a distributed antenna system involves the use of radio frequency (RF) antenna coverage areas, also referred to as “antenna coverage areas.” The antenna coverage areas are provided by remote antenna units in the distributed antenna system. Remote antenna units can provide antenna coverage areas having radii in the range from a few meters up to twenty (20) meters as an example. If the antenna coverage areas provided each cover a small area, there are typically only a few users (clients) per antenna coverage area. This allows for minimizing the amount of RF bandwidth shared among the wireless system users. It may be desirable to provide antenna coverage areas in a building or other facility to provide indoor distributed antenna system access to clients within the building or facility. It may also be desirable to employ optical fiber to distribute RF communications signals to provide an optical fiber-based distributed antenna system. Distribution of RF communications signals over optical fiber can include Radio-over-Fiber (RoF) distribution. Benefits of optical fiber include increased bandwidth.
Remote antenna units in a distributed antenna system can be configured to distribute RF communication signals in multiple radio bands (i.e., frequencies or ranges of frequencies), as opposed to a single radio band. Distributing RF communications signals in multiple radio bands in an antenna coverage area increases flexibility of the distributed antenna system. In this scenario, client devices configured to communicate in different radio bands can be supported in a given antenna coverage area provided by the remote antenna unit. However, providing remote antenna units that support multiple radio bands can also limit capacity in the distributed antenna system. The bandwidth of the remote antenna unit is split among the multiple radio bands thus reducing the capacity of each supported radio band in a given antenna coverage area.
To offset a reduction in capacity in remote antenna units supporting multiple radio bands, additional remote antenna units could be provided. The remote antenna units could be co-located and each configured to support only one of the radio bands. However, providing additional remote antenna units increases the cost of the distributed antenna system. Further, additional head-end equipment may be required to be deployed to support the additional remote antenna units. Providing additional remote antenna units to provide additional capacity may be delayed after initial installation and provided as needed, but higher installation costs may be associated with retrofitting an existing installation with additional remote antenna units.